Transcript 01-Anatomy of Kidney..

Anatomy of The
Kidney
Objectives
By the end of the lecture, the student should be able to
describe the:
 Anatomical features of the kidneys:
position, extent, relations, hilum, peritoneal coverings.
 Internal structure of the kidneys:
Cortex, medulla and renal sinus.
 The vascular segments of the kidneys.
 The blood supply and lymphatics of the kidneys.
• Kidneys are retroperitoneal
paired organs.
• Each kidney lies , on the
posterior abdominal wall,
lateral to the vertebral
column
• In the supine position, the
kidneys extend from
approximately T12 to L3.
• The right kidney is slightly
lower than the left kidney
because of the large size of
the right lobe of the liver.
• With contraction of the
diaphragm during
respiration, both kidneys
move downward in a
vertical direction (high of
one vertebra, 1 inch, 2.5
cm).
Position of the kidneys
Color, Shape & Dimensions
• The kidney is a reddish brown, beanshaped organ with the dimensions 12 x
6 x 3cm.
• Although they are similar in size and
shape, the left kidney is slightly longer
and more slender than the right
kidney, and nearer to the midline.
• Each kidneys has:
Convex upper & lower ends.
Convex lateral border.
Convex medial border at both ends,
but its middle shows a vertical slit
called the hilum.
Internally the hilum extends into a large
cavity called the renal sinus.
Hilum
Renal
sinus
Renal sinus
Hilum & Renal sinus
• The hilum transmits, from
anterior to posterior, the renal
vein, renal artery & the ureter
(VAU).
• Lymph vessels & sympathetic
fibers also pass through the
hilum.
• The renal sinus contains the
upper expanded part of the
ureter called the renal pelvis.
• Perinephric fat is continues
into the hilum and the sinus
and surrounds all these
structures.
V
A
U
Coverings
1. Fibrous capsule:
Is closely adherent to its surface
2. Perirenal fat:
covers the fibrous capsule.
3. Renal fascia:
Condensation of areolar
connective tissue that lies
outside the Perirenal fat and
encloses the kidney and the
suprarenal gland.
4. Pararenal fat:
Lies external to the renal
fascia, is part of the
retroperitoneal fat.
The last 3 structures support the
kidneys and hold it in position on
the posterior abdominal wall.
Relations
I- Anterior
The anterior
surface of both
kidneys are related
to numerous
structures, some
with an intervening
layer of peritoneum
and others lie
directly against the
kidney without
peritoneum.
Left kidney:
• A small part of the superior pole,
along the medial border , is
covered by left suprarenal gland.
• The rest of the superior pole is
covered by the intraperitoneal
stomach and spleen.
• The retroperitoneal pancreas
covers the middle part of the
kidney.
• Its lower lateral part is directly
related to the left colic flexure
and beginning of descending
colon.
• Its lower medial part is covered
by the intraperitoneal jejunum.
right kidney
• A small part of the upper pole
is covered by right suprarenal
gland.
• The rest of the upper part of
anterior surface is related to
the liver and is separated by a
layer of peritoneum.
• The 2nd part of duodenum
lies directly in front of the
kidney close to its hilum.
• The lower lateral part is
directly related to the right
colic flexure and, on its lower
medial side, is related to the
intraperitoneal small
intestine.
Posterior Relations
Posteriorly, the right and left kidneys
are almost related to similar structures.
Left kidney:
Diaphragm
Costodiaphragmatic
recess of the pleura
11th & 12th ribs; last
intercostal space
Psoas major
Quadratus lumborum
transversus
abdominis.
Subcostal (T12),
iliohypogastric &
ilioinguinal nerves.
Right kidney:
• Diaphragm
• Costodiaphragmatic
recess, of the
pleura
• 12th rib, last
intercostal space
• Psoas major
• Quadratus
lumborum,
transversus
abdominis.
• Subcostal (T12),
iliohypogastric &
ilioinguinal nerves.
Vertebrocostal & Renal Angles
• The angle between the
last rib and the lateral
border of erector spinae
muscle is occupied by
kidney and is called the
‘Renal angle’
• The Vertebrocostal
angle is occupied by the
lower part of the pleural
sac.
E
r
e
c
t
o
r
s
p
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n
a
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Vertebrocostal angle
Renal angle
Internal structure
• Each kidney consists of an
outer renal cortex and an
inner renal medulla.
• The renal cortex is a
continuous band of pale tissue
that completely surrounds the
renal medulla.
• Extensions of the renal cortex,
the renal columns project into
the inner aspect of the kidney,
dividing the renal medulla into
discontinuous aggregations of
triangular-shaped tissue, the
renal pyramids.
Renal column
Cortex
Renal
pyramid
Medulla
• The bases of the renal
pyramids are directed
outward, toward the cortex,
while the apex of each
renal pyramid projects
inward, toward the renal
sinus.
• The apical projection (renal
papilla) is surrounded by a
minor calyx
• In the renal sinus, several
minor calices unite to form
a major calyx, and two or
three major calices unite to
form the renal pelvis, which
is the funnel-shaped
superior end of the ureters.
Base
Apex, Renal papilla
Minor
calyx
Major
calyx
Renal
pelvis
Arterial Supply
Lobar
arteries
• The renal artery arises from the
aorta at the level of the second
lumbar vertebra.
• Each renal artery divides into 5
segmental arteries that enter the
hilum of the kidney, 4 in front of
the renal pelvis and one behind it.
• They are distributed to the
different segments of the kidney.
• Each segmental artery gives rise to
number of lobar arteries, each
supplies a renal pyramid.
• Before entering the renal
substance, each lobar artery gives
off two or three interlobar
arteries.
Segmental
arteries
Interlobar
arteries
• The interlobar arteries
Arcuate arteries
run toward the cortex
on each side of the
renal pyramid.
• At the junction of the
cortex and the medulla,
the Interlobar arteries
give off the arcuate
arteries, which arch
over the bases of the
pyramids.
• The arcuate arteries
give off several
interlobular arteries
that ascend in the
cortex and give off the Interlobular
arteries
afferent glomerular
arterioles.
Interlobar
arteries
Segmental branches &
vascular segments of kidneys
1
3
5
4
2
• Each kidney has 5
segmental branches
and is divided into 5
vascular segments:
1. Apical.
2. Caudal.
3. Anterior Superior.
4. Anterior Inferior.
5. Posterior.
1
3
5
4
2
• Abdominal aorta
• Renal artery
• Segmental arteries
• lobar arteries
• Interlobar arteries
• Arcuate arteries
• Interlobular
arteries
•
afferent glomerular
arterioles
Blood Supply
• Inferior vena
cava
• Renal vein
• Interlobar veins
• Arcuate veins
• Interlobular
veins
Venous Drainage
• Both renal veins drain to the
inferior vena cava.
•
•
•
•
•
The left renal vein is three times longer
than the right (7.5 cm and 2.5 cm).
So, for this reason the left kidney is the
preferred side for live donor
nephrectomy.
It runs from its origin in the renal hilum,
posterior to the splenic vein and the
body of pancreas, and then across the
anterior aspect of the aorta, just below
the origin of the superior mesenteric
artery.
The left gonadal vein enters it from
below and the left suprarenal vein,
usually receiving one of the left inferior
phrenic veins, enters it above but nearer
the midline.
The left renal vein enters the inferior
vena cava a little above the right vein.
•
The right renal vein is behind the 2nd
part of the duodenum and sometimes
behind the lateral part of the head of
the pancreas
Lymphatic
Drainage:
• The lymph
vessels follow
the arteries.
• Lymph drains to
the lateral aortic
lymph nodes
around the
origin of the
renal artery.
Nerve Supply:
The nerve supply is the renal sympathetic plexus. The afferent
fibers that travel through the renal plexus enter the spinal cord in
the 10th, 11th, and 12th thoracic nerves.